Water container

ABSTRACT

A jerrycan comprises a container housing having four sidewalls, a base and a top. The jerrycan includes a manual pump unit and a water filter cartridge disposed within the housing, together with an externally mounted tap coupled to the water filter cartridge. A carrying handle is integrally formed with the top. When constructed the jerrycan is sealed and is both water- and air-tight. The container housing includes at least one internal brace member consisting of a hollow tube integral with the sidewalls.

FIELD OF THE INVENTION

The present invention relates to a water container for removingimpurities from water to provide sterile, safe drinking water.

BACKGROUND TO THE INVENTION

Water is heavy. Delivering it over even short distances is timeconsuming and expensive. It requires long logistic chains to maintainsupplies. This problem is acutely evident during military orhumanitarian operations

If personnel choose to drink water from the surrounding environment theyrun the risk of becoming struck down by disease through the ingestion ofbacteria or viruses living naturally in the water.

Our published International patent application WO2008/037969 discloses awater bottle having a water filter which removes sediments and otherdeposits from the water and has a retention of greater than log 6(99.9999%) of bacteria, cysts, parasites and fungi, and greater than log4 (99.99%) of viruses from the water.

One well known container used to carry larger volumes of water is theubiquitous “jerrycan”, originally designed at the outbreak of World WarII, and much copied since. Although originally manufactured from pressedsteel, modern jerrycans are now typically manufactured from plastics invarious sizes from 5L to 20L. Jerrycans are still used extensively bythe military and aid agencies to carry clean supplies of water tolocations where it is needed.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a container forwater comprising:

-   -   a container housing for holding water having at least one        internal brace member coupled between opposing side wall        portions of the walls of the container to resist deformation of        the container housing;    -   a water filter that extends into the container housing;    -   an output valve coupled to the water filter; and,    -   means for establishing a pressure differential across the walls        of the container housing,        wherein the water filter comprises one or more membranes which        are effective to pass water in preference to air under the        influence of the pressure differential.

In a preferred embodiment, the container is a jerrycan, preferablyhaving a capacity of between 5 and 20 litres. The jerrycan is preferablymade from plastic materials, and in particular, water-grade high-densitypolyethylene (HDPE). Plastic jerrycans can be made using techniques wellknown in the art, such as rotational moulding or blow moulding. However,metal jerrycans are also envisaged as being suitable for use. Inaddition, the present invention can be applied to larger water vesselssuch as water butts.

Preferably, the at least one brace member consists of a hollow tubewhich is integral to the sidewall portions of the container housing. Assuch, in addition to providing structural reinforcement to the housingto resist deformation when under load, particularly when the containeris pressurised with air, the one or more internal brace members mayfunction to enable the container of the invention to be attached to loadcarriage systems. Each hollow tube forms an open channel connectingopposing sidewall portions through which it is envisaged support rods orthe like can be inserted. Such rods may for example function as a wheelaxle, allowing the container to transported on wheels.

Preferably, one or more sidewalls of the container housing comprise apattern of indentations to provide enhanced structural rigidity atselected locations, thereby to resist deformation of the sidewalls whenunder load. These indentations may be configured to provide channels forreceiving strapping applied around the circumference of the container.

In a preferred embodiment, the housing further comprises a base having aplurality of flat feet. Preferably, the base has pitched portions toresist deformation of the base. The one or more sidewalls and the topwall may also include pitched portions. The pitched portions in the baseand side walls provide further structural reinforcement to enable to thecontainer housing to resist deformation under load.

Preferably, the means for establishing a pressure differential comprisesa pump. More preferably, the pump is a manually operated pump.Preferably, the pump is a piston pump comprising a non-return valvethrough which air may be passed into the container, and a piston shaftthrough which a piston head may be moved such that air is passed throughthe non-return valve.

In one preferred embodiment, the pump is removable from the device toallow the liquid reservoir to be refilled.

As an alternative to a pump, the container may simply comprise apressure valve for connection to a separate source of pressurised gas.

Preferably, the container further comprises a pressure regulator. Forexample, the pressure regulator may include a release valve adapted torelease water and/or air if the pressure in the container exceeds apredetermined level.

Preferably, the output valve is a tap. Preferably, the tap has anexternal spout that is angled downwards to promote the flow of any waterremaining in the spout after the tap has been closed. Optionally, theexternal spout may comprise a hose fitting for receiving a removablewater hose pipe.

Preferred water filters for use with the present invention are suitablefor ultrafiltration, that is to remove all particles of a size greaterthan 0.01 microns. In another preferred embodiment the filter issuitable for nanofiltration or reverse osmosis. Reverse osmosis filtersare capable of removing everything (including salts and oils) apart frompure water (H₂O) from a liquid. Nanofiltration removes particles of asize greater than 0.001 microns (including aqueous salts).

Water is passed through the water filter under a pressure differential.This allows the water to be passed through finer filters than would bepossible if the container were not pressurised.

A pore size of less than or equal to 25 nanometres is sufficient toremove most microbiological matter from the liquid, including viruses,thereby providing safe drinking water and a far more effective portablewater filtration system than has previously been available. However, foradditional security, preferred embodiments of the invention have a poresize of less than or equal to 20 nanometres, and more preferably have apore size of less than or equal to 15 nanometres.

As is known in the art, the pore size of a material is in fact anaverage of the individual sizes of the pores (or holes) in the material,since it is inevitable that any material comprising a large number ofpores will include some variation in these individual sizes. Preferredfilters for use in the present invention have a tightly defineddistribution of pore sizes such that the difference between the maximumpore size and the average pores size is minimized. Preferably, thestandard deviation of the pore size distribution is less than 30% of theaverage pore size, and more preferably is less than 15% of the averagepore size. In preferred embodiments of the invention, the filter has amaximum pore size of less than or equal to 30 nanometres, morepreferably, less than or equal to 25 nanometres, and most preferablyless than or equal to 20 nanometres. In other embodiments, the maximumpore size may be even lower in order to perform nanofiltration orreverse osmosis, for example.

Preferably, the water container of the present invention will filterwater with a pressure differential of any size. For example, theoperating pressure differential of a preferred embodiment is preferablygreater than 10 kPa, more preferably in the range of 50 kPa-1500 kPa,more preferably in the range of 100 kPa-1000 kPa, more preferably 150kPa-300 kPa.

The water filter of the present invention is preferably a membranefilter. It preferably comprises at least one hydrophilic membrane.Hydrophilic membranes are attractive to water and therefore water ispassed through them in preference to other liquids and to gases. In thisway, not only is the filtration offered by the preferred embodimentsimproved, but it is possible to use the filter even when it is notcompletely immersed in the liquid.

Preferably, the membranes are capillary hollow fibre membranes. Thesemembranes act to filter the water as only particles smaller than theirpore size may pass through them. The fibre membranes may incorporatecarbon or other chemical elements, or reverse osmosis membranes. Acombination of different types of filter membranes may be included inthe filter. These may include ultrafiltration, nanofiltration andreverse-osmosis membranes.

Once water enters through the wall of a capillary membrane under theinfluence of a pressure differential it is transferred along itstube-like structure to the output. As a result, water may enter at anypoint along the membrane wall and reach the output while also beingfiltered.

Preferably, the filter lies substantially along an entire length of thecontainer housing, ensuring that any water is in contact with themembranes. Preferably, the filter lies along over 70% of said length ofthe container, more preferably over 80%, more preferably over 90%. Thismeans that when a pressure differential exists between the inside of thecontainer housing and the outside atmosphere across the walls of thehousing, and the output valve is open, water in the container will passthrough the filter to the output valve substantially regardless of theorientation of the device.

Preferably, the water filter comprises an annular housing having anouter wall having a plurality of holes therethrough. In one preferredembodiment of the present invention the filter is substantiallycylindrical. Preferably, the holes are distributed across substantiallythe whole length of the filter.

The filter is preferably removable from the container. This allows thefilter to be cleaned and replaced as required.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of the present invention will now be described in detail withreference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a jerrycan with a partial cutawaysection;

FIG. 2 is a sectional view of the jerrycan of FIG. 1;

FIG. 3 is a top elevation of the jerrycan of FIG. 1;

FIG. 4 is an end elevation of the jerrycan of FIG. 1; and,

FIG. 5 is a partial view of the base of the jerrycan of FIG. 1.

DETAILED DESCRIPTION

FIGS. 1 and 2 show a jerrycan 10 designed in accordance with the presentinvention. The jerrycan 10 comprises a container housing 11 having foursidewalls 12-15, a base 16 and a top 17. The jerrycan 10 includes amanual pump unit 18 and a water filter cartridge 19 disposed within thehousing 11, together with an externally mounted tap 20 coupled to thewater filter cartridge 19. A carrying handle 21 is integrally formedwith the top 17. When constructed the jerrycan 10 is sealed and is bothwater- and air-tight.

The water filter cartridge 19 is preferably of the type described inInternational patent application number PCT/GB2007/003623 (Internationalpublication number WO2008/037969) filed on 25 Sep. 2007. Filters of thistype are made from a matrix of hollow fibre membranes 22 which typicallyhave a mean pore size which is capable of ultra-filtration. As such, thefilter cartridge 19 is effective to remove bacteria, viruses, cysts,parasites, fungi and all other water-born pathogens. In fact, such afilter removes all microbiological matter from the water to providesafe, sterile drinking water.

The preferred fibre membranes 22 used in preferred embodiment of thepresent invention have a retention of greater than log 6 (99.9999%) ofbacteria, cysts, parasites and fungi, and greater than log 4 (99.99%) ofviruses from the water. The fibre membranes 22 also remove sediments andother deposits from the water.

The manual pump unit 18 provides the required pressure differentialacross the walls of the jerrycan 10 to drive water through the walls ofthe hollow fibre membranes 22 and thereafter along the length of thefibre membranes 22 to their open ends at the tap 20 when the tap 20 isopened.

Providing a water filter cartridge 19 such as that described aboveallows the user to use water from a wide range of sources, includingopen sources of water, that is effectively rendered safe to drink.

Fibre membranes suitable for use with the present invention areavailable commercially, for example X-flow (™) capillary membranes fromNorit (www.norit.com) may be used. This hollow fibre ultra-filtrationmembrane 22 is effective to screen all turbidity, bacteria as well asviruses.

The water filter cartridge 19 abuts the base 16 and is removablyattached to the top of the container 10 by a screw cap compressionfitting 23. An advantage of this architecture is that, although fullysealed when in place, the water filter cartridge 19 may be removed forcleaning or replacement at any time. In this way, the entire jerrycan 10need not be replaced if the water filter cartridge 19 becomes damaged insome way.

The manual pump unit 18 shown in the Figures is preferably of the typedescribed in detail in International patent application numberPCT/GB2007/003623 (International publication number WO2008/037969) filedon 25 Sep. 2007. It is attached to the jerrycan 10 by a screw capcompression fitting 24 to ensure a fluid tight seal. Like the waterfilter cartridge 19, the entire pump unit 18 is designed to be removedfrom the jerrycan 10.

The pump shown in this preferred embodiment is a simple 1:1 pump, inthat the pressure that the user must overcome to actuate the pump isequal to the pressure in the container. Nevertheless, it is possible touse ratcheting, or gearing, systems in accordance with the pump of thepresent invention. These mechanisms allow easier hand actuation of thepump 18 (and consequently enable to pressure inside the container to beincreased to a greater level than would otherwise be possible).

The jerrycan 10 also incorporates an additional carbon filter 25 throughwhich water can pass before leaving through the tap. Carbon filters areknown to be effective in the removal of chemicals from water. The carbonfilter 25 used in the preferred embodiment is an active carbon filter,although other types of carbon-based filters (such as charcoal filters)may be adopted.

In order to remove impurities from water, the pump 18 is removed fromthe container housing 11 and untreated water is poured into the jerrycan10. The pump 18 is then re-attached to the container housing 11 and thepump handle 26 is unlocked and repeatedly moved from a withdrawnposition to a closed position thereby moving the piston head 27 up anddown through the piston shaft 28. This has the effect of forcing airthrough a non-return valve 29, thereby increasing the pressure withinthe container 11. When the user opens the tap 20, the internal pressureforces the water through the hollow tube membranes 22 within the waterfilter cartridge 19 and ultimately out of the container 11 through thetap 20 for the user to collect.

The housing 11 further comprises a notch 36 located below the tap, whichenables easy filing of other containers, such as standard army issuewater bottles and other water carrying devices, with dean water from thejerrycan 10.

The jerrycan 10 has a number of internal brace members 30 that extendbetween opposing sidewall portions 13,15 of the container 11 to provideenhanced resistance to deformation of the container walls when loadedwith water and pressurised with air. As shown, each brace member 30consists of a hollow tube 31 which is integral to the sidewall portions13,15 of the container housing 11. The hollow tube 31 is profiled in afluted manner with a pitch angle Θ of 5°. This shape is akin to athree-dimensional arch shape. The fluting design disperses the loadevenly, in order to disperse the stress across a greater surface area,thereby enhancing the rigidity provided by the brace member. The pitchangle can be selected according to requirements.

The hollow brace members 30 enable the jerrycan 10 to be attached toload carriage systems. In particular, each hollow tube 31 provides anopen channel connecting opposing sidewall portions 13,15 through whichit is envisaged support rods or the like can be inserted. Such rods mayfor example function as a wheel axle, allowing the container to betransported on wheels.

The sidewalls 12-15 of the container housing 11 are formed with apattern of indentations 32 to provide enhanced structural rigidity atselected locations, thereby resisting deformation of the sidewalls whenunder load. These indentations 32 are configured to provide channels forreceiving strapping applied around the circumference of the container 11(not shown).

As shown in FIGS. 3 and 4, the end walls 12,14 and the top wall 17include pitched portions 33. The pitched portions 33 provide furtherstructural reinforcement to enable to the container housing 11 to resistdeformation under load, particularly when a pressure differential hasbeen established across the walls of the container. These pitch angles ein this example are between 3° and 7°, but again, these can be variedaccording to requirements. These pitch angles also allow for thejerrycan 11 to be wedged into tight spaces, for example in a vehicle.

As shown in FIG. 5, the base 16 has a number of flat feet 34 configuredto resist deformation of the base 16. The base 16 has pitched portions35 which also help resist deformation of the base 16 under load.Conventional jerrycans are formed with a recessed base which has beenfound to be susceptible to “blow out” when the jerrycan is pressurisedso that the jerrycan can not remain upright. The jerrycan 10 of thepresent invention is designed such that the areas of the base that aremost likely to deform under load are located above the level of theplurality of feet 34. The shape of the base 16 is designed to allow foran inevitable degree of expansion of the housing 11 under load, whilstresisting deformation of the feet 34 in order to prevent the jerrycan 10from toppling over. The plurality of feet 34 in the configuration shownalso aid the manufacture of the jerrycan 11. They are constructed in theline of draw and this reduces the complexity of the moulding toolrequired, thereby reducing the over cost of production.

1. A jerrycan for holding water, the jerrycan comprising: a containerhousing for holding water having at least one internal brace membercoupled between opposing sidewall portions of the walls of the containerto resist deformation of the container housing, the at least oneinternal brace member consisting of a hollow tube which is integral tothe sidewall portions of the walls of the container; a base having aplurality of flat feet with pitched portions therebetween; a waterfilter that extends into the container housing; an output valve coupledto the water filter; and, means for establishing a pressure differentialacross the walls of the container housing, wherein the water filtercomprises one or more membranes which are effective to pass water inpreference to air under the influence of the pressure differential.
 2. Ajerrycan according to claim 1, in which the container has a capacity ofbetween 5 and 20 litres.
 3. A jerrycan according to claim 1, in whichthe container housing is made from water grade high-density polyethylene(HDPE).
 4. (canceled)
 5. A jerrycan according to claim 1, in which oneor more sidewalls of the container housing comprise a pattern ofindentations to provide enhanced structural rigidity at selectedlocations, thereby to resist deformation of the sidewalls when underload.
 6. A jerrycan according to claim 5, in which the indentations areconfigured to provide channels for receiving strapping applied, in use,around the circumference of the container.
 7. (canceled)
 8. A jerrycanaccording to claim 6, in which one or more of the sidewalls and top wallhas pitched portions to resist deformation.
 9. A jerrycan according toclaim 1, in which the means for establishing a pressure differentialcomprises a pump.
 10. A jerrycan according to claim 9, in which the pumpis removable to facilitate refilling of the container housing.
 11. Ajerrycan according to claim 1, in which the container comprises apressure valve for connection to a separate source of pressurised gas.12. A jerrycan according to claim 1, further comprising a pressureregulator.
 13. A jerrycan according to claim 1, in which the outputvalve comprises a tap.
 14. A jerrycan according to claim 13, in whichthe tap has an external spout that is angled downwards to promote theflow of any water remaining in the spout after the tap has been closed.15. A jerrycan according to claim 1, in which the water filter isadapted to remove all particles of a size greater than 0.01 microns, andpreferably greater than 0.001 microns.
 16. A jerrycan according to claim1, in which the water filter comprises at least one hydrophilicmembrane.
 17. A jerrycan according to claim 16, in which the at leastone membrane is a capillary hollow fibre membrane.
 18. A jerrycanaccording to claim 16, in which the filter lies substantially along theentire depth of the container housing, ensuring that any water is incontact with the membranes when the housing is in an upright position19. A jerrycan according to claim 1, in which the water filter is aremovable cartridge.
 20. (canceled)
 21. (canceled)
 22. A jerrycanaccording to claim 1, in which the hollow tube has a fluted profile. 23.A jerrycan according to claim 22, in which the container has a capacityof between 5 and 20 litres.
 24. A jerrycan according to claim 17, inwhich the filter lies substantially along the entire depth of thecontainer housing, ensuring that any water is in contact with themembranes when the housing is in an upright position.